Given the practical infinity of visual objects and scenes in the world, and the relatively few neurons tasked to represent them, what shapes or features should any given neuron learn to encode to be most efficient?
Reid's group found that neurons tasked with suppressing brain activity seem to be randomly wired, putting the lid on local groups of neurons all at once rather than picking and choosing.
We reasoned that if a neuron coded task difficulty then it would respond similarly to the most difficult stimuli, independently of the boundary position.
Johnston, K., Levin, H. M., Koval, M. J. & Everling, S. Top-down control-signal dynamics in anterior cingulate and prefrontal cortex neurons following task switching.
The results indicated that the majority of the hippocampal formation neurons showed task condition- and/or reinforcement situation-dependent responses, suggesting a crucial role of the hippocampal formation in representation of overlapping serial events in episodic memory.
Throughout training, a high percentage of striatal (57%) and motor cortex (55%) neurons were task related; i.e., changed their firing rate while mice were running on the rotarod.
We did not preselect neurons for task-related responses; instead we advanced microelectrodes until we could isolate neuronal activity before starting the search tasks.
Single neuron activity tracking task progress during a self-ordered task or of successively presented sensory stimuli as well as anticipatory activity related to expectation of reward has also been reported in the LPFC62,63,64.
Given the computational advantages of top-down potentiation, it is unsurprising that electrophysiology research has provided a wealth of evidence, demonstrating that lateral frontal cortical neurons represent task-relevant inputs, rules and responses54,55,56.
There are theories, he says--that by evolving to favor one hand, our species freed up some of our gray matter to use for other neuron-greedy tasks, like speaking a language.
